1. Field of the Invention
The invention pertains to the field of ventilation systems. More particularly, the invention pertains to ventilation and filtration systems for personal use.
2. Description of Related Art
Allergens and other contaminants (e.g. pollen, mold, car exhaust, and smoke) in public places cause discomfort for many people. It is well established that poor quality of breathed air in the workplace results in reduced productivity at work. Air quality is also poor on airplanes, and travelers are often exposed to diseases from other passengers. Mold and toxins from cleaning products found in schools often cause problems with children, resulting in unhealthy learning environments due to heightened allergic sensitivity. In hospitals, airborne diseases can cause patients to develop nosocomial infections like tuberculosis, varicella, and rubeola.
With the problem of poor indoor air quality at an epidemic level, to the point that there is now such a thing as “Sick Building Syndrome,” and with people spending the vast majority of their time inside, it is essential to find solutions that meet the needs of the millions of people who suffer due to transmitted diseases and allergic reactions to airborne pollutants. Several companies currently offer personal air ventilation and room air purifications devices, ranging from small units that one wears around the neck (e.g. Wein Personal Air Purifier and Ionmax Personal Ionic Air Purifier), to tabletop models (e.g. Oreck XL Tabletop Air Purifier), to free-standing floor models that filter the air for an entire room (e.g. Oreck XL Tower Air Purifier, Sharper Image Ionic Breeze, Hamilton Beach TrueAir HEPA air purifier).
Conventional air purification devices perform well to reduce the ambient levels of contaminants in a room; however, they fail to adequately filter the air as it travels from the floor to the mouth. As a result, significant contaminants, both particulate and gaseous, have an opportunity to enter the airstream in this region, greatly reducing the perceived effect of the room air purifier. Introduction of contaminants into the thermal plume include resuspension of particulate matter from the floor (particularly from dirty carpeting), volatile organic compound outgassing from carpets, furniture, and equipment, as well as ambient levels of both particles and volatile organic compounds. Thermal plume, as defined herein, is a plume generated by gas rising from above a heat source because warm gas is less dense than the surrounding cooler gas.
To improve the indoor air quality, air filters have been widely used in building HVAC systems, portable room air cleaners and even automobiles. Particles are essentially the major target of these filters. Recently, with the increase in concern over other indoor pollutants including, but not limited to, volatile organic compounds, bacteria and other microorganisms, as well as other undesired gases and airborne pollutants, composite/combination filters have been developed that are aimed to remove pollutants other than particles.
There remains a gap in filtration systems when considering the needs of the individual, especially in terms of the personal environment. Large, bulky, floor models are effective in general removal of pollutants from a room; however, they tend to be noisy, expensive, and consume large amounts of power. At the other end of the spectrum, those that are wearable (i.e. the true personal ventilation unit for the individual), do not work well, and many release ozone as a bi-product of the filtration process, which is then breathed in by the user. In light of this, there is a need in the art for improved personal ventilation systems.